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Saturday, October 22, 2016

A Package from Hyderabad: Farhan's BITX 40 Module Arrives in Virginia

I am having a really EXCELLENT radio morning here at SolderSmoke East coast HQ.  I made some progress on the Armand HRO receiver -- just squaring away some of the too-long leads and improving the shielding a bit.  Then I was looking out the window as the mailman arrived.  What was that little box he was leaving us?  Wow! A box from Hyderabad!  The BITX 40 module arrived, wrapped in a very interesting piece of Hyderabad newspaper. Very FB. Thanks Farhan.  I will surely be writing and talking about this rig in the weeks to come.

UPDATE:  I just realized that the BITX module fits very nicely into a TenTec TPC-45 cabinet that Armand gave me a while back.  TRGHS.

Thursday, October 20, 2016

Cool Jazz from New Zealand as Heard on a Homebrew Superhet Receiver (VIDEO)

I'm making slow but steady progress on this one.  The origin of the project was the beautiful National HRO dial and gearbox that Armand WA1UQO gave me. 

I decided to use a 455 kHz IF because;
1) That was the IF of the old HRO receivers (the ones that won WWII)
2) I had a nice TOYO CM455 crystal mechanical filter that would be good for SSB.
3) I figured it would be easy to add in a wider filter that would be good for AM shortwave listening.
4) I like to keep the IF below the frequency of the VFO.

The wide filter turned out to be harder than I thought, but I think I have finally achieved the selectivity I was looking for.  I'll have a switch on the front panel that will allow me to go from "AM-Wide" to "SSB Narrow." The switch will change the filters and the detectors, and will turn the BFO on and off.

Still to do:  I need a high-pass filter to knock down RFI from nearby AM broadcast transmitter. And an RF gain control would be nice.

I'm really glad Radio New Zealand is there.  It provides welcome relief from the shortwave fire and brimstone.   Radio Romania is also doing a fine job on shortwave.

Wednesday, October 19, 2016

The Last Hallicrafters Transceiver...REBORN! TWICE!

Pete Juliano and his colleague Giovanni Manzoni led me this morning to the happy land of Hallicrafters hybrid nostalgia.

It all started with Pete's latest blog post:

I admit that I had never even heard of the Hallicrafters FPM rigs.  Pete's (uh, I mean Giovanni's) video show's Pete's junk-box rebuild of the old rig.  Very nice.   Note the presence of the Si5351...

I needed more background info, so I turned to YouTube.  This led me to more old friends:  Dale Parfitt W4OP has a really nice video of his rebuild of the Halli FPM rig (see above).  From his video we learn why Dr. Juliano prescribed a dose of Si5351 for the patient:  Dale tells us that VFO instability was a major problem with this rig.   Dale fixed his with the addition of an X-Lock board from yet another friend of SolderSmoke: Ron G4GXO of Cumbria Designs. 

Dale really out-did himself by building an add-on accessory box for the FPM.  Very nice.  I especially liked the addition of the W3NQN passive audio filter for CW.   I always have misgivings about adding audio filters to Direct Conversion receivers -- this will reduce QRM, but you are still listening to both sides of zero beat.  But when you add a sharp CW audio filter to an SSB superhet you will end up with true "single signal reception."  FB Dale.  

Please send Pete Juliano and Giovanni Manzoni some positive feedback and words of encouragement.  Please urge them to keep up the good work on the blog and the videos.  Theirs is sometimes a lonely task -- without feedback it can sometimes seem like putting messages in a bottle and throwing them into the digital sea.   Please let them know that their work is being seen!  Leave some positive comments on Pete's blog.  (No snark please -- The Radio Gods will retaliate if you harsh N6QW's mellow.)

Monday, October 17, 2016

Oz Tektronix 'Scope Repair (in Juliano Blue)

Rob is a braver ham than I.  When my Tek 465 quit, I tried to fix it, but quickly chickened out.
Very nice that he painted his in Juliano Blue.

Dear Bill and Pete, 

I do enjoy your podcast, and I must present an offering to the "Gods of Homebrew", 
An on-line find of an old Tek 545 oscilloscope presented a chance to enjoy the warmth of 100+ tubes (once repaired)
The outside was heavily scratched, the inside looked like a chicken coup, but no major bits missing or broken. 
Lots of cleaning, testing all tubes,(using the excellent uTracer tube tracer),  replacing the broken 3, remounting the cooling fan, lots of reading about tube oscilloscopes, adjusting the trigger circuit, rebuilding 3 electrolytic power supply capacitors, sandblasting the cabinet and a coat of BLUE paint
Voila,  the joy of (visual) oscillation!     (1MHz 2V p-p)


Sunday, October 16, 2016

Colin M1BUU's New Receiver Project

Hi Pete,
Just checking in :-)
I have actually been melting solder recently. I decided to build a little CW receiver. I love my regenerative RX that I built as a teenager, but after all these years, I'm tired of constantly tweaking the controls!
My project is a 20m CW only superhet receiver with a 9MHz home brew filter. I'm using the SI5351 for the oscillators. I originally thought I would cover multiple  bands, but for now I have the parts for 20m coverage. I might tinker with other bands at a later point.
I'm using your LBS code on the Arduino, the one for 20m with 9MHz IF. I haven't applied power to the rig yet but it's not far off fully built. I tweaked the Arduino sketch using my Uno and tonight I have successfully transferred the code to a Pro Mini. (Code went into Pro Mini on first attempt - amazing!).
73 for now,
Colin M1BUU

Designer: Douglas Bowman | Dimodifikasi oleh Abdul Munir Original Posting Rounders 3 Column